Kinetics and Mechanism of Oxidation Induced Contraction of MgAl2O4Spinel Carbon Composites Reinforced by Al4C3in situReaction

Kinetics and mechanism of oxidation induced contraction of MgAl(2)O(4)spinel carbon composites reinforced by Al(4)C(3)in situreaction were researched in air using vertical high temperature thermal dilatometer from 25 degrees C to 1 400 degrees C. It is shown that oxidation induced contraction of MgAl(2)O(4)spinel carbon composites reinforced Al(4)C(3)in situreaction is the common logarithm of oxidation timetand the oxygen partial pressurePinside MgAl(2)O(4)spinel carbon composites reinforced by Al(4)C(3)in situreaction in air at 1 400 degrees C is as follows:P=F(-2.75x10(-4)A+2.13x10(-3)) lnt. The nonsteady diffusion kinetic equation of O(2)at 1 400 degrees C inside the composites is as follows:J=D(e)lnt. Acceleration of the total diffusional flux of oxygen inside the composites at 1 400 degrees C is in inverse proportion to the oxidation time. The nonsteady state effective diffusion coefficientD(e)of O-2(g) inside the composites decreases in direct proportional to the increase of the amount of metallic aluminium. The method of preventing the oxidation induced contraction of MgAl(2)O(4)spinel carbon composites reinforced by Al(4)C(3)in situreaction is to increase the amount of Al. The slag erosion index of MgO-Al(2)O(3)spinel carbon composite reinforced by Al(4)C(3)in situreaction is 0.47 times that of MgO-CaO brick used in the lining above slag line area of a VOD stainless steel-making vessel. HMOR of MgO-Al(2)O(3)spinel carbon composite reinforced by Al(4)C(3)in situreaction is 26.7 MPa, HMOR of the composite is 3.6 times the same as that of MgO-CaO brick used in the lining above slag line area of a VOD vessel. Its service life is two times as many as that of MgO-CaO brick.